Disposable diapers, incontinence pads and the like are known as examples of absorbent articles that absorb liquid such as liquid excretions. These absorbent articles typically include absorbent bodies made of liquid absorbent fibers, such as pulp fibers, formed into a predetermined shape.
However, recently, there are cases where a superabsorbent polymer (hereinafter, also referred to as SAP) in a particulate form is used as the main material of the absorbent body and liquid absorbent fibers are not used, or, if used, are used in an auxiliary manner.
An example of an apparatus that manufactures such an absorbent body is disclosed in PTL 1. With such an apparatus, the absorbent body is formed at a predetermined pitch in the transport direction by dropping and depositing the SAP at intervals on a continuous web which is transported in the transport direction.
On the other hand, PTL 2 discloses a method of measuring an amount of SAP that is scattered at intervals on an absorbent body which has pulp fibers as its main material. More specifically, a capacitance-based sensor is provided at a predetermined position in the transport direction of the absorbent body, and a distribution of the amount of SAP in the transport direction is measured based on a change of capacitance while the absorbent body is passing below the sensor.